Chembiochem : a European journal of chemical biology 2016 7 21() doi 10.1002/cbic.201600329
The size, functional group diversity and three-dimensional structure of proteins often allow these biomolecules to bind disease-relevant structures that challenge or evade small-molecule discovery. Additionally, folded proteins are often much more stable in biologically relevant environments, compared to their peptide counterparts. We recently showed that helix-grafted-display-extensive resurfacing and elongation of an existing solvent exposed helix in a Pleckstrin Homology (PH) domain-leads to a new protein that binds a surrogate of HIV-1 gp41, a validated target for inhibition of HIV-1 entry. Expanding on this work, we prepared a number of human-derived helix-grafted-display PH domains with varied helix length, and measured properties relevant to therapeutic and basic research applications. In particular, we show that some of these new reagents express well as recombinant proteins in E. coli, are relativey stable in human serum, bind a mimic of pre-fusogenic HIV-1 gp41 in vitro and in complex biological environments, and significantly lower the incidence of HIV-1 infection of CD4-positive cells.